出现取消出现对null指针的引用咋办

Question

#include
#include <stdlib.h>

#define MAXSIZE 100
typedef struct {
    int elem[MAXSIZE];
    int last;
}SeqList;
SeqList Lq;
SeqList* Createselist() {
    SeqList* Lq;
    Lq = (SeqList*)malloc(MAXSIZE * sizeof(SeqList));
    Lq->last = -1;
    return Lq;
}
void CreateList(SeqList* Lq)
{
    int i;
    printf("请输入表长:\n");
    scanf("%d", &Lq->last);
    for (i = 0;i < Lq->last;i++)
    {
        printf("请输入表中的第%d个元素", i + 1);
        scanf("%d", &Lq->elem[i]);
    }
}



int  Locate(SeqList* Lq, int e)
{
    int i = 0;        /*i为扫描计数器，初值为0，即从第一个元素开始比较*/
    while ((i <= Lq->last) && (Lq->elem[i] != e))/*顺序扫描表，直到找到值为key的元素, 或扫描到表尾而没找到*/
        i++;
    if (i <= Lq->last)
        return(i + 1);  /*若找到值为e的元素，则返回其序号*/
    else
        return(-1);  /*若没找到，则返回空序号*/
}
void main()
{
    SeqList* Lq;
    int x, i;
    Lq = Createselist();
    CreateList(Lq);
    printf("请输入要查找的数字x：");
    scanf("%d", &x);
    Locate(Lq, x);

}

Answer 1

明明有个全局的Lq，为啥又定义一堆的函数内变量也叫Lq
代码在VS2010下可以运行的